Track ball base structure

ABSTRACT

A track ball base structure comprises a single-piece body having a housing being composed of a plurality of standing plates in the top of the body with extruding portions in the upper end of which to get secure connection to a cover, a central circular recess with an opening bottom to hold a ball therein, a plurality of ball bearing holes evenly distributed around the upper rim of the circular panel in the housing with an inner rectangular plate inside the uppermost of each hole for admitting ball bearings therein and at the same time holding them in place, multiple pairs of locking means and slots in both sides of the body for locking the detecting system as well as fixing the body substantially onto an integrated circuit plate. The present invention is characterized by providing a track ball base structure in a non-assembly manner. Therefore, the number of component parts required for the track ball is reduced and clearly any damage occurring under interconnection for each part can be eliminated.

FIELD OF THE INVENTION

The present invention relates generally to a track ball base structureand more particularly to a single-piece body that provides severalfunctions so as to reduce the number of component parts required for atrack ball and give a more rigid base structure.

BACKGROUND OF THE INVENTION

Conventionally, a track ball assembly includes a cover, a ball, ahousing to admit the ball, a plurality of ball bearings which are evenlydistributed around an inner surface of the housing to support the ball,a seat having locking means thereon and an encoder wheel which isincorporated with a photoemitter as well as a photodetector together toform a detecting system to control the movement of a visual cursor on amonitor.

But some disadvantages exist in the aforementioned design. First, thethorough base structure assembly consisting of a housing and a seat tohold the encoder wheel and the ball is accomplished by linking severalparts and may suffer damages from any mistake trying to interconnecteach part. Second, it is known that the ball bearing is kept partiallyinside a hole in order to provide an anti-friction interface to supportand permit the ball rotate freely in the housing. But, the problem isthe whole ball bearing will be pushed down into the hole and then getjammed if acted upon by a excessive force. Third, the encoder wheel andthe housing are connected together to the seat by spring biasing meanswhile this arrangement is cumbersome. Finally, a block on which aphotoemitter and a photodetector are located in pair is only releasablyengaged with the seat.

SUMMARY OF THE INVENTION

Accordingly, it is a principal objective of the present invention toprovide a track ball base structure that overcomes the problems withinthe aforementioned prior art.

It is another objective of the present invention to provide a track ballbase structure which is a single-piece body and able to offer a housing,a seat and locking means simultaneously without the prior assemblymanner. Therefore, the number of component parts required for the trackball is reduced and clearly the possible damages occurring underinterconnection for each part can be eliminated.

It is still another objective of the present invention to provide atrack ball base structure that in the uppermost of the hole which isused to keep the ball bearing, there is a rectangular plate so that theball bearing can be held in place all the time.

In accordance with the present invention, the track ball base structureis a single-piece body including a housing which is composed of aplurality of standing plates in the top of the body so as to receive aball and an encoder wheel, a central circular recess with an openingbottom for holding the ball, a plurality of ball bearing holes, andmultiple pairs of locking means and slots in both sides of the body forlocking the detecting system as well as fixing the body substantiallyonto an integrated circuit plate.

The above and other objectives, features and advantages of the inventionwill become readily apparent from the following detailed descriptionthereof which is to be read in connection with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is an exploded perspective view of a track ball along with anintegrated circuit plate;

FIG. 2 is a perspective view of a track ball;

FIG. 3 is a top plan view of a track ball base structure along with thepositioned encoder wheel and ball bearings;

FIG. 4 is a perspective view of another preferred embodiment of thetrack ball base structure of the invention;

FIG. 5 is a bottom perspective view of a track ball base structure alongwith ball bearings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings in detail and in particular to FIG. 1, whereinthe components of a track ball shown in an exploded manner include acover 13 with a locking slot 131; a ball 10 and two encoder wheels 14being arranged perpendicular to each other and a rub tube 141 fitted toeach encoder wheel 14 so that the encoder wheel 14 rotates incoincidence with the action of the ball 10 by direct contact with therub tube 141 since the existence of interface frictions; a single-piecebody 11 having a housing which is composed of a plurality of standingplates 115 in the top of the body 11 so as to receive the ball 10 andthe encoder wheel 14, a central circular recess 12 with an openingbottom to hold the ball 10, a plurality of ball bearing holes 113 evenlydistributed around the upper rim of the circular panel in the housingwith an inner rectangular plate 123 inside the uppermost of each hole toadmit ball bearings 15 and at the same time hold them in place, twostrip slots 111 and the corresponding pairs of locking means 112a, 112bworking together in order to hold the encoder wheel 14 wherein theholding condition can be enhanced due to a lateral gravity force fromthe ball 10 if sitting in the central circular recess 12, two lockingholes 17 in platforms 116a, 116b outer to the housing through which thesingle-piece body 11 can be screwed up onto an integrated circuit plateby a bolt.

FIG. 2 is a perspective view of a track ball. Referring to FIG. 1 and 2,the track ball assembly is accomplished by using the cover 13 to confinethe ball 10 between the cover 13 and the single-piece body 11 and thenrotate the cover 13 slightly so that the locking slots 131 move into theextruding portions 114a, 114b in the upper end of standing plates 115 toget securely lock.

Referring to FIG. 3, it is a top plan view of a track ball basestructure along with the positioned encoder wheel 14 and ball bearings15. This figure clearly shows the distribution of every portion in theball track base structure of the present invention.

Referring to FIG. 4, it is another preferred embodiment of a track ballbase structure of the present invention, wherein the couples of ballbearings 15 and ball bearing holes 113 are replaced by the same shape ofbump 151 which is made of an anti-friction material so that a muchsimpler structure can be formed while the same function retained.

Referring to FIG. 5, it is a bottom perspective view of a track ballbase structure along with ball bearings wherein especially thebracket-shaped fixture 16 is provided to substantially engage with ablock on which a photoemitter and a photodetector are located in pairincorporated with the encoder wheel 14 to control the movement of avisual cursor on a monitor.

Having described the specific preferred embodiments of the presentinvention with reference to the accompanying drawings, it will beappreciated that the present invention is not limited to that preciseembodiments and that various changes and modifications can be effectedtherein by one of ordinary skill in the art without departing from thescope or spirit of the invention as defined by the appended claims.

What is claimed is:
 1. A track ball base structure comprising asingle-piece body having:a housing to receive a ball and an encoderwheel therein being composed of a plurality of standing plates in thetop of said body with extruding portions in the upper end of which toget secure connection to a cover; a central circular recess with anopening bottom to hold said ball therein; a plurality of ball bearingholes evenly distributed around the upper rim of the circular panel insaid housing with an inner rectangular plate inside the uppermost ofeach said hole for admitting ball bearings therein and at the same timeholding them in place; two strip slots and the corresponding pairs oflocking means working together in order to hold said encoder wheelwherein the holding condition can be enhanced due to a lateral gravityforce from said ball if sitting in said central circular recess; twolocking holes in platforms outer to said housing through which saidsingle-piece body can be screwed up onto an integrated circuit plate bya bolt; a bracket-shaped fixture in the bottom of said single-piece bodybeing provided to substantially engage with a block on which aphotoemitter and a photodetector are located in pair.
 2. A track ballbase structure according to claim 1, wherein the couples of said ballbearings and said ball bearing holes are replaced by the same shape ofbump which is made of anti-friction material so that a much simplerstructure can be formed while the same function retained.